Heterixalus is a genus of frogs within the family

Hyperoliidae The Hyperoliidae, or sedge frogs and bush frogs, are a large family of small to medium-sized, brightly colored frogs which contain more than 250 species in 19 genera. Seventeen genera are native to sub-Saharan Africa. In addition, the monotypic g ...

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

Madagascar Madagascar, officially the Republic of Madagascar, is an island country that includes the island of Madagascar and numerous smaller peripheral islands. Lying off the southeastern coast of Africa, it is the world's List of islands by area, f ...

. It is the

sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...

to the genus ''

Tachycnemis The Seychelle Islands treefrog or Seychelles treefrog (''Tachycnemis seychellensis'') is a species of frog in the family Hyperoliidae. It is endemic to Seychelles. Its natural habitats are subtropical or tropical moist lowland forest, rivers, s ...

''. These frogs are commonly referred to as Madagascar reed frogs. ''Heterixalus'' species are colorful, small to medium-sized frogs ranging from 18-40 mm in length. They have webbing on both the front and back feet, and the digits and webbing are typically yellow and orange. The tips of the digits are circularly enlarged, and the lateral

metatarsalia The metatarsal bones or metatarsus (: metatarsi) are a group of five long bones in the midfoot, located between the tarsus (skeleton), tarsal bones (which form the heel and the ankle) and the phalanges of the foot, phalanges (toes). Lacking indi ...

are connected. Distinct among Malagasy frogs, the

pupil The pupil is a hole located in the center of the iris of the eye that allows light to strike the retina.Cassin, B. and Solomon, S. (1990) ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company. It appears black becau ...

is shaped as a "vertical rhomboid," with the anterior side pointed outward and the posterior side semicircular. Additionally,

vomerine teeth The vomer (; ) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones. The vomer forms t ...

are absent. Males are slightly smaller than females and can be told apart from the latter by weakly developed

nuptial pads A nuptial pad (also known as thumb pad, or nuptial excrescence) is a secondary sex characteristic present on some mature male frogs and salamanders. Triggered by androgen hormones, this breeding gland (a type of mucous gland) appears as a spike ...

and a single, distensible

vocal sac The vocal sac is the flexible Biological membrane, membrane of skin possessed by most male frogs and toads. The purpose of the vocal sac is usually as an amplification of their mating or advertisement call. The presence or development of the voca ...

. ''Heterixalus'' species tend to be very variable in color and patterning, and up to three species can be found at the same location. Therefore, while many species do have characteristic coloration, the best way to distinguish species and species complexes are by call. Typically, ''Heterixalus'' species live outside dense

forests A forest is an ecosystem characterized by a dense community of trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological functio ...

, where they inhabit sunlit pools,

swamps A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

and ricefields.

Species

''Heterixalus'' contains 11 species:

References

{{Taxonbar, from=Q518269 Hyperoliidae Amphibian genera Endemic frogs of Madagascar Taxa named by Raymond Laurent Taxonomy articles created by Polbot Taxa described in 1944